Summary of work: Formulae have been developed for the computation of percent body fat from anthropometric measurements. Anthropometric data have been obtained on BLSA participants since the study was initiated. We now have adequate body composition data from Dual Energy X-ray Absorptiometry studies to derive formulae for the computation of percent fat based upon multivariate prediction equations on men and women of all adult ages. Thus computation of Percent Body Fat (a better index of obesity than the Body Mass Index) is now available on participants on visits going back 40 years. In collaboration with two scientists from the National Institute for Longevity Sciences in Nagoya, comprehensive analyses of the relation of anthropometric and metabolic variables is being performed. Body Mass Index and Percent Body Fat (from DEXA) as well as estimates of the pattern of fat distribution are being related to ten well-established coronary heart disease risk factors (systolic and diastolic blood pressures, fasting and two-hour post-glucose plasma glucose concentration, fasting plasma insulin and insulin resistance (HOMA), and four plasma lipid moieties) are being examined in younger and older men and women. Waist circumference has emerged as the dominant measure of fat distribution. The NHLBI "Evidence Report" on obesity was issued in July 1998 and provided single health cutpoints for the waist circumference measurements in men (102 cm) and in women (88 cm); thus two zones for the body fat distribution were established. No "grey zone" for waist circumference was defined, although the BMI range was stratified into six diagnostic categories. A 1998 WHO report however recommended cutpoints of 94 and 102 cm for men and 80 and 88 cm for women, thus creating normal, moderately high risk, and very high risk zones. We have tested the applicability of these WHO standards to younger and older men and women. Results of the analyses in BLSA participants show clearly that both the BMI and waist circumference remain very significant determinants of the traditional coronary heart disease risk factors in old age.